Ternary adduct {[W(CN)8]3−,[Pt(en)2]2+,[W(CN)8]3−} in aqueous solution and crystal structure of [Pt(en)2]3[W(CN)8]2·4H2O with infinite linear W · · · Pt chains

Abstract

A new donor–acceptor system based on [W(CN)8]3− and [Pt(en)2]2+ has been characterised in aqueous solution and in the solid state. Spectroscopic studies indicate formation of the ternary adduct {[W(CN)8]3−,[Pt(en)2]2+,[W(CN)8]3−} in aqueous solution. The aggregate has been described as a mixed-valence species with weak-to-moderate coupling between metal centres. The solid [Pt(en)2]3[W(CN)8]2·4H2O exhibits the simultaneous presence of {WV, PtII, WV} ←→ {WIV, PtIV, WIV} electronic isomers and can be interpreted in terms of ground state borderline electronic localised-to-delocalised species. The structure of [Pt(en)2]3[W(CN)8]2·4H2O consists of one-dimensional infinite chains formed by tungsten and platinum moieties linked through hydrogen bonding from ethane-1,2-diamine nitrogens and water molecules to nitrogens of all cyano ligands.